1. Field of the Invention
The present invention relates to a cam lock assembly. More particularly, it relates to a reversible cam lock assembly useful for preventing either clockwise or counterclockwise rotation, depending on its orientation, of a movable member relative to a stationary member.
2. State of the Art
Typical operatory stools are provided with a body support arm, located above the seat of the stool, for supporting the body of a user in a multitude of positions. Depending on the actual operation being performed by the user, the body support arm may be required to support the back, the abdomen or chest, or the arms of the user. It is desirable that the body support arm be adjustable in a variety of positions to accommodate the different operating positions adopted by the user. Various adjustable body support stools are described in the prior art. For example, U.S. Pat. No. 3,338,626 describes a stool on which the body support arm can be shifted horizontally about the stool seat and also can be tilted with respect to the plane of the seat. U.S. Pat. No. 4,085,967 describes a body support stool supplied with a clutch assembly to permit lateral movement of the body support arm with respect to the stool seat.
It is generally known that an eccentric cam can be utilized to lock two telescoping members and prevent their relative rotation in a predetermined direction. A stool for use in a dental operatory is available which employs a cam lock to prevent movement of a body support arm about a vertical support member. On a right-handed stool, one cam lock which prevents clockwise rotation of the support arm is provided. On a left-handed stool, another different cam lock is provided to prevent counterclockwise rotation of the support arm about a vertical support member. The necessity of two different cam locks requires that two separate parts be available during manufacturing so that either right-handed or left-handed stools can be produced.
The present invention obviates the necessity of having two separate cam locks by providing, in a single, unitary assembly, a cam lock which can be used for either right-handed or left-handed stools to resist clockwise or counterclockwise movement, respectively.